1. Field of the Invention
The invention relates to a driving force transmitting device which gives a drive force to a driven member which does not have a drive force, by engaging itself with the driven member.
2. Description of Related Art
Traditionally, there exists a driving force transmitting device which gives a driving force by engaging the transmitting device with a driven member to which the driving force is applied.
As the driving force transmitting device, for example, as a driving force transmitting device comprising: a casing having a pair of opposing walls in which a supporting shaft projects from the other opposing wall toward a penetrated hole formed on one opposing wall of the pair of opposing walls; a transmitting gear which is supported in a state parallel to the supporting shaft in the casing and is rotated upon reception of the driving force; a joint gear which is supported by the supporting shaft to mesh with a transmitting gear and is configured to be movable along the supporting shaft in a meshing state; a leading tip part which protrudes from the penetrated hole being formed with an engaging part with respect to the driven member; an urging device which urges the joint gear to the protruding direction which passes through a penetrated hole from the casing; and a stopper which restricts a movement amount of the joint gear in a protruding direction along a supporting shaft thereof (For example, see JP-3283189-B).
As a driven member driven by such a driving force transmitting device, for example, there enumerates a paper feeding tray which is attachably/detachably configured to be mounted on an inkjet type or an electrophotographic type image forming device main body.
In this paper feeding tray, provided on an outer bottom plate of a box-shaped tray main body provided is an inner bottom plate whose one end is supported by an outer bottom plate. The input shaft which passes through between the other end of the inner bottom plate and the outer bottom plate and protrudes outside the tray is pivotally supported by the tray main body, a tongue-shaped lever is provided at a site positioned between the other end of the inner bottom plate and the outer bottom plate, of an input shaft, and an engaged part which engages with an engaging part of the driving force transmission device and one end protruding outside the tray, of the input shaft, is provided with an engaged part which engages with an engaging part of the driving force transmitting device.
The paper feeding tray constructed like this, the engaged part engages the engaging part, the tongue lever fixed to the input shaft pivots and lifts up the inner bottom plate by giving the rotational force of the driving force transmitting device main body to the input shaft side and paper sheets which is supported by the inner bottom plate is maintained at a predetermined height sufficient enough to feed the paper sheets to the image forming apparatus.
However, in the above-mentioned driving force transmitting device, since the shaft-like leading tip part of the joint gear is protruded from the penetrated hole and the protruded leading tip part is formed with an engaging part for engaging with the driven member, the driven member and the driving force transmitting device require a considerable depth length and it becomes one drawback to the downsizing of a product. Moreover, since a connecting length between the driven member and the driving force transmitting device is long, even if a slight displacement of the centering occurrences, such a long part of the connecting length flexes and absorbs the slight displacement of centering to connect both. A bending moment is likely to be applied to a joint gear. It is feared that the generation of deviated wear generates in a gear train within the casing including that joint gear and the occurrence of noise of the gear train are main causes of a failure. The invention was made taking account of the drawback and the failure, and an object of the invention is to provide a driving force transmitting device and a driving force transmitting mechanism, which can solve the above problems.